Premium
The First Ring‐Enlargement of a 1‐Azabicyclo[1.1.0]butane to a 1‐Azabicyclo[2.1.1]hexane
Author(s) -
Mlostoń Grzegorz,
Heimgartner Heinz
Publication year - 2006
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200690044
Subject(s) - chemistry , morpholine , butane , yield (engineering) , cycloaddition , hexane , ring (chemistry) , bicyclic molecule , adduct , medicinal chemistry , stereochemistry , organic chemistry , catalysis , materials science , metallurgy
The reactions of 3‐phenyl‐1‐azabicyclo[1.1.0]butane ( 4 ) with dimethyl dicyanofumarate (( E )‐ 8 ) and dimethyl dicyanomaleate (( Z )‐ 8 ) lead to the same mixture of cis ‐ and trans ‐4‐phenyl‐1‐azabicyclo[2.1.1]hexane 2,3‐dicarboxylates ( cis ‐ 11 and trans ‐ 11 , resp.; Scheme 3 ). This result of a formal cycloaddition to the central CN bond of 4 is interpreted by a stepwise reaction mechanism via a relatively stable zwitterionic intermediate 10 , which could be intercepted by morpholine to give a 1 : 1 : 1 adduct 12 , which undergoes a spontaneous elimination of HCN to yield the fumarate 13 ( Scheme 4 ).